Method for encoding video using effective differential motion vector transmission method in omnidirectional camera, and method and device

ABSTRACT

The present invention relates to an image encoding and decoding technique for a high-definition video compression method and device for an omnidirectional security camera, and more specifically, to a method and a device whereby a differential motion vector is effectively transmitted, and an actual motion vector is calculated using the transmitted differential motion vector, and thus motion compensation is performed.

RELATED APPLICATIONS

This application is a continuation application of the InternationalPatent Application Serial No. PCT/KR2016/013592, filed Nov. 24, 2016,which claims priority to the Korean Patent Application Serial No.10-2016-0155541, filed Nov. 22, 2016. Both of these applications areincorporated by reference herein in their entireties.

TECHNICAL FIELD

The present invention relates to an image encoding and decodingtechnique in a high-quality video compression method and apparatus foran omnidirectional security camera. And more particularly, the presentinvention relates to a method and apparatus for efficiently transmittinga differential motion vector, calculating an actual motion vectorthrough a transmitted differential motion vector, and thereby performingmotion compensation.

BACKGROUND

In recent years, there has been a growing demand for a variety ofdevices and systems for security, due to increasing social anxiety dueto crime such as indiscriminate crimes against unspecified persons,retaliatory crimes against certain targets, and crimes against sociallyvulnerable classes. In particular, security cameras (CCTV) can be usedas evidence for crime scenes or impression descriptions of criminals,thus demand for personal safety as well as national demand isincreasing. However, due to the limited conditions in transmission orstorage of acquired data, image quality deteriorates or there is a realproblem that can be saved as a low-quality image. In order to utilize avariety of security camera images, a high-quality compression methodcapable of storing a high-quality image with a low data amount isrequired.

In most image compression, since the encoding/decoding efficiency isimproved through the compression between images, various inventions thateffectively compress the images are proposed. An effective motion vectortransmission technique is an important technique for improving interprediction performance.

SUMMARY

An object of Some embodiments of the present invention is to effectivelycompress image data acquired via an omnidirectional security camera.

It is to be understood, however, that the technical problems of thepresent invention is not limited to the above-described technicalproblems, and other technical problems may exist.

As a technical mean for achieving the above object, an apparatus andmethod for decoding an image according to an embodiment of the presentinvention adaptively sets a prediction candidate of a motion vector toan image using a virtual motion vector, and performs motion compensationafter calculating an actual motion vector using the prediction candidateand a transmitted differential motion vector. To this end, an embodimentof the present invention includes a parsing unit for parsing imageinformation and camera information, an information acquisition unit forcalculating and predicting image information using parsed information, avirtual coordinate determination unit for determining a virtual imagecoordinate system using image information, a motion vector predictioncandidate setting unit for setting a motion vector prediction candidatein a virtual coordinate, a virtual motion vector calculation unit forcalculating a virtual motion vector by using a predictive motion vectorand a transmitted differential motion vector, a motion vector conversionunit for converting the virtual motion vector into an actual motionvector in an image, and a motion compensation performing unit forperforming motion compensation using an actual motion vector.

In order to improve inter prediction coding efficiency, the presentinvention determines a virtual coordinate by reflecting characteristicsof an image, calculates a virtual motion vector using a predictivemotion vector and a differential motion vector in a virtual coordinate,and then performs motion compensation.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram showing a configuration of a video decodingapparatus according to an embodiment of the present invention.

FIG. 2 illustrates a position of a neighboring block to be used as acandidate of a predictive motion vector in a motion vector predictionaccording to an embodiment of the present invention.

FIG. 3 is an embodiment in which there is no candidate of a predictivemotion vector according to an embodiment of the present invention.

FIG. 4 illustrates a relationship between a virtual coordinate of apredictive motion vector and an actual image coordinate according to anembodiment of the present invention.

FIG. 5 illustrates a method of performing inter prediction in anembodiment of the present invention.

FIG. 6 illustrates a method of performing inter prediction in anembodiment of the present invention.

FIG. 7 illustrates a process of calculating a motion vector to performmotion compensation in an embodiment of the present invention.

FIG. 8 is a diagram for explaining the concept of virtual coordinates inan embodiment of the present invention.

FIG. 9 illustrates various types of omnidirectional projection in anembodiment of the present invention.

FIG. 10 illustrates a method of constructing a frame using a projectedimage in an embodiment of the present invention.

FIG. 11 illustrates a method of constructing a frame using a projectedimage in an embodiment of the present invention.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present invention will be described indetail with reference to the drawings attached hereto, so that thoseskilled in the art can easily carry out the present invention. Thepresent invention may, however, be embodied in many different forms andshould not be construed as limited to the embodiments set forth herein.In order to clearly illustrate the present invention, parts not relatedto the description are omitted in the drawings, and similar parts aredenoted by similar reference numerals throughout the specification.

Throughout this specification, when a part is referred to as being‘connected’ to another part, it includes not only a case where it isdirectly connected but also a case where the part is electricallyconnected with another part and there are other devices in between. Inaddition, in the specification, when an element is referred to as being“comprising” an element, it is understood that the element may furthercomprise other elements without excluding other elements as long asthere is no contrary description.

The term “˜step” or “step of˜” used in the present specification doesnot imply a step for ˜.

Also, the terms such as first, second, etc. may be used to describevarious components, but the components should not be limited by theterms. The terms are used only for the purpose of distinguishing onecomponent from another.

In addition, the components shown in the embodiments of the presentinvention are shown independently to represent different characteristicfunctions, and it does not mean that each component is composed ofseparate hardware or one software constituent unit. That is, eachconstituent unit is described separately for convenience of explanation,and at least two constituent units of constituent units may be combinedto form one constituent unit or one constituent unit may be divided intoa plurality of constituent units to perform a function. The integratedembodiments and the separate embodiments of each of these components arealso included in the scope of the present invention without departingfrom the essence of the present invention.

First, the terms used in the present application will be brieflydescribed as follows.

The video decoding apparatus may be a device included in the serverterminal such as a personal security camera, a private security system,a military security camera, a military security system, a personalcomputer (PC), a notebook computer, a portable multimedia player (PMP),a wireless communication terminal, a smart phone, a TV applicationserver, and a service server. The video decoding apparatus may bevarious devices including a user terminal such as various devices, acommunication device such as a wired/wireless communication network,Communication modem to perform communication etc., various programs forinter-prediction or intra-prediction or for decoding an image, a memoryfor storing data, and a microprocessor for calculating and controllingby executing a program.

In addition, an image encoded into a bitstream by an encoder may betransmitted in real time or in non-real time via a wired or wirelesscommunication network such as the internet, a local area wirelesscommunication network, a wireless LAN network, a WiBro network, a mobilecommunication network, or via a cable, Universal Serial Bus(USB), andthe like to an image decoding apparatus. The encoded image may bedecoded and restored into an image, and then reproduced.

In general, a moving picture may be composed of a series of pictures,and each picture may be divided into a coding unit such as a block. Itis to be understood that the term ‘picture’ described below may bereplaced with other terms having an equivalent meaning such as an image,a frame, etc. The term ‘coding unit’ may be replaced with other termshaving equivalent meanings such as a unit block, block, and the like.

Hereinafter, embodiments of the present invention will be described indetail with reference to the drawings. In the description of the presentinvention, duplicate descriptions will be omitted for the samecomponents.

FIG. 7 illustrates a process for performing motion compensationaccording to an embodiment of the present invention. In the embodimentof the present invention, the decoder parses information of an imageacquisition camera and image information from the bitstream transmittedfrom the encoder (701). The information may be transmitted in a sequenceunit, in an SEI message unit, or in an image group or a single imageunit. The information of the camera included in the bitstream mayinclude the number of cameras that acquire an image at the same time, aposition of the camera, an angle of the camera, a type of the camera,and a resolution of the camera. The image information may include aresolution, a size, bit-depth, a projection shape, a preprocessing type,related coefficient information, and virtual coordinate-relatedinformation for the image acquired through the camera. According to theembodiment, all of the information may be transmitted. Only a part ofthe information may be transmitted and the other part of the informationmay be calculated or derived by the decoder. In addition to theabove-mentioned information, information required by the decoder may betransmitted together.

The decoder obtains information for decoding from the transmitted andparsed information (702). According to an embodiment, the transmittedinformation may be directly used as information for decoding, or theinformation for decoding may be derived or calculated using thetransmitted information. Referring to the above embodiment, information,which is related to whether a motion vector of a block decoded at theboundary of the image opposite to the boundary block of the imagedescribed in FIGS. 3 and 4 is to be included in the candidate group whenthe predictive motion vector group is determined and whether theembodiments in which a reference block illustrated in FIG. 6 is dividedby a picture boundary are applied, may be information transmitted oracquired through the corresponding image information. The divided blocksmay exist at a boundary different from each other. The decoderdetermines a virtual coordinate based on the acquired information (703).

Hereinafter, embodiments of the present invention will be described indetail with reference to the drawings attached hereto, so that thoseskilled in the art can easily carry out the present invention. Thepresent invention may, however, be embodied in many different forms andshould not be construed as limited to the embodiments set forth herein.In order to clearly illustrate the present invention, parts not relatedto the description are omitted in the drawings, and similar parts aredenoted by similar reference numerals throughout the specification.

Throughout this specification, when a part is referred to as being‘connected’ to another part, it includes not only a case where it isdirectly connected but also a case where the part is electricallyconnected with another part and there are other devices in between. Inaddition, in the specification, when an element is referred to as being“comprising” an element, it is understood that the element may furthercomprise other elements without excluding other elements as long asthere is no contrary description.

The term “˜step” or “step of˜” used in the present specification doesnot imply a step for˜.

Also, the terms such as first, second, etc. may be used to describevarious components, but the components should not be limited by theterms. The terms are used only for the purpose of distinguishing onecomponent from another.

In addition, the components shown in the embodiments of the presentinvention are shown independently to represent different characteristicfunctions, and it does not mean that each component is composed ofseparate hardware or one software constituent unit. That is, eachconstituent unit is described separately for convenience of explanation,and at least two constituent units of constituent units may be combinedto form one constituent unit or one constituent unit may be divided intoa plurality of constituent units to perform a function. The integratedembodiments and the separate embodiments of each of these components arealso included in the scope of the present invention without departingfrom the essence of the present invention.

First, the terms used in the present application will be brieflydescribed as follows.

The video decoding apparatus may be a device included in the serverterminal such as a personal security camera, a private security system,a military security camera, a military security system, a personalcomputer (PC), a notebook computer, a portable multimedia player (PMP),a wireless communication terminal, a smart phone, a TV applicationserver, and a service server. The video decoding apparatus may bevarious devices including a user terminal such as various devices, acommunication device such as a wired/wireless communication network,Communication modem to perform communication etc., various programs forinter-prediction or intra-prediction or for decoding an image, a memoryfor storing data, and a microprocessor for calculating and controllingby executing a program.

In addition, an image encoded into a bitstream by an encoder may betransmitted in real time or in non-real time via a wired or wirelesscommunication network such as the internet, a local area wirelesscommunication network, a wireless LAN network, a WiBro network, a mobilecommunication network, or via a cable, Universal Serial Bus(USB), andthe like to an image decoding apparatus. The encoded image may bedecoded and restored into an image, and then reproduced.

In general, a moving picture may be composed of a series of pictures,and each picture may be divided into a coding unit such as a block. Itis to be understood that the term ‘picture’ described below may bereplaced with other terms having an equivalent meaning such as an image,a frame, etc. The term ‘coding unit’ may be replaced with other termshaving equivalent meanings such as a unit block, block, and the like.

Hereinafter, embodiments of the present invention will be described indetail with reference to the drawings. In the description of the presentinvention, duplicate descriptions will be omitted for the samecomponents.

FIG. 1 illustrates a decoding apparatus for performing image decoding ona block-by-block basis using division information of a block accordingto an embodiment of the present invention. The decoding apparatus mayinclude at least one of an entropy decoding unit 110, an inversequantization unit 120, an inverse transform unit 130, an interprediction unit 140, an intra prediction unit 150, an in-loop filterunit 160, or a reconstructed image storage unit 170.

The entropy decoding unit 110 decodes the input bitstream 100 andoutputs decoded information such as syntax elements and quantizedcoefficients. The output information includes various information forperforming decoding and may include information on the image and imageacquisition cameras. The image information and image acquisitioninformation may be transmitted in various forms and units and may beextracted from a bitstream or may be calculated or predicted usinginformation extracted from a bitstream.

The inverse quantization unit 120 and the inverse transformation unit130 receive the quantized coefficient, perform inverse-quantization andinverse-transform, and output a residual signal.

The inter prediction unit 140 calculates a motion vector using adifferential motion vector extracted from the bitstream and a predictivemotion vector, and generates a prediction signal by performing motioncompensation using the reconstructed image stored in the reconstructedimage storage unit 170. In this case, accurate prediction of thepredictive motion vector may be a very important factor in efficientmotion vector transmission because it can reduce the amount ofdifferential motion vector. The motion vector of the neighboring blockof the current block to be decoded are used as the candidate of thepredictive motion vector as shown in FIG. 2 . FIG. 2 is an embodiment ofthe present invention. The shape of a decoding block and the positionrelationship between a motion vector candidate and a current decodingblock may vary according to an embodiment of the present invention. InFIG. 2 , the shape of the decoding block may be a square, a non-squarehaving an arbitrary size or a block having an arbitrary shape accordingto an embodiment. The motion vector candidate may be determined invarious forms according to the shape of the decoding block and thecoordinate within the image. The motion vector candidate may berepresentative of a motion vector of a neighboring block of a currentblock to be decoded, a motion vector of a co-located block of areference image, a motion vector of a chrominance componentcorresponding to the decoding block, a motion vector of a neighboringblock of a chrominance component corresponding to the decoding block, amotion vector resulting from scaling, based on a temporal positionrelation between a reference image and a decoding image, a motion vectorof a neighboring block of the decoding block. FIG. 3 illustrates a casewhere there is no motion vector of a spatial neighboring block accordingto the position relationship of the current decoding block in the imageor the characteristics of the image when constructing the predictivemotion vector candidate group. In FIG. 3 , a gray hatched blockrepresents a block that does not exist or does not have a motion vector.According to the embodiment, the presence or absence of a candidate fora spatial predictive motion vector of a neighboring block may vary. FIG.3 illustrates four embodiments. For example, if the current block to bedecoded is positioned at the right edge of the image, the block with thehatched position cannot exist in the image and the motion vector cannotexist, as illustrated in FIG. 3A. In this case, a motion vector of ablock in a different position may be used as illustrated in FIG. 4 . Asillustrated in FIG. 4 , the decoding block located at the right edge ofthe image does not have the decoding block at the hatched position, butthe decoding block at the R position exists. Therefore, the motionvector of the decoding block at the R position may also be used as thepredictive motion vector candidate. The embodiment of FIG. 4 may beapplied to the case of FIGS. 3 (B), (C) and (D). This is a predictableembodiment by a person having ordinary knowledge, and a detaileddescription thereof will be omitted. The motion vector may be calculatedby obtaining the predictive motion vector through this process andadding the differential motion vector, which is transmitted through thebitstream, to the predictive motion vector. The motion compensation ofthe inter prediction unit 140 is performed based on the obtained motionvector and the reference image.

Like the embodiment of the present invention, the encoder may transmitthe syntax including the related information to the decoder in order touse the motion vector of the block located away from the currentdecoding block rather than the motion vector of the neighboring block asthe predictive motion vector. This transmission my be available atvarious levels, such as a sequence unit, a frame unit, a slice unit, atile unit. Herein, sequence, frame, slice, and tile may be replaced withother term that denote a group of coding units. Information whether touse the embodiment of the present invention and the related informationmay be directly transmitted according to the embodiment, or the decodermay calculate and estimate using other information transmitted from theencoder.

The embodiment of the present invention may be equally applied not onlyto the determination of the predictive motion vector candidate group butalso to the motion vector merging (MV merge). An merging candidatemotion vector is required for motion vector merging in the encoder, anda predictive motion vector candidate group in the embodiment of thepresent invention may be used as a candidate group for motion vectormerging. That is, in the decoder according to the embodiment of thepresent invention, when the current decoding block corresponds to themotion vector merging block using the same motion vector as theneighboring block, the current decoding block may be merged with one ofthe motion vector candidate blocks described with reference to FIG. 3and FIG. 4 . The corresponding information may be obtained from thedecoder through parsing and decoding of the bitstream.

The intra prediction unit 150 generates a prediction signal of a currentblock by performing spatial prediction using pixel values of a decodedneighboring block adjacent to the current block to be decoded.

The prediction signals output from the inter prediction unit 140 and theintra prediction unit 150 are summed with the residual signal, and thereconstructed image generated through the summing is transmitted to thein-loop filter unit 160.

The reconstructed picture to which the filtering is applied in thein-loop filter unit 160 is stored in the reconstructed image storageunit 170 and may be used as a reference picture in the inter predictionunit 140.

FIG. 5 illustrates an embodiment of motion compensation for a blockapplied in inter prediction. FIG. 5A shows motion compensation for a Pslice when only one reference image is used, and FIG. 5B shows motioncompensation for a B slice when two reference images are used. In themotion compensation for the B slice, the reference image may be one offrames which are decoded previously regardless of POC and stored in thereference image frame buffer. The related information is transmittedfrom the encoder to the decoder together with index information andmotion information (differential motion vector, merge index, scaleinformation, etc.) and the block may be decoded using the same. Whenmotion compensation is performed using the predictive motion vector, thedifferential motion vector information or the motion vector merginginformation, the reference block as shown in FIG. 5 is generally locatedinside the reference image. In the embodiment of the present invention,the motion vector calculated for the reference between images is shownin the same form as FIG. 6 . The reference block indicated by the motionvector may be referred. If the correlation between the left edge and theright edge of the image is high depending on the characteristics of theimage, the encoding efficiency may be improved through the embodiment ofthe present invention. The regions B and C of FIG. 6 are located on bothedges at different positions in the image plane, but they are blockslocated at the same position in the x-coordinate. When the both edgesare connected to each other, the shape becomes as shown in FIG. 8A. Thatis, according to the embodiment of the present invention, it is possibleto perform motion compensation in a form in which both edges having highcorrelation are connected. If the image has a high correlation betweenthe upper edge and the lower edge, the motion compensation may beperformed in the form shown in FIG. 8B. The embodiment of the presentinvention may be performed regardless of the number of reference images.The embodiment of the present invention may be applied to a first casewhere one of the two reference blocks is referred to within the imageand the other one is referred to at the image edge as shown in FIG. 6Bor a second case where both reference blocks are referred to at theimage edge.

As shown in the embodiment of FIG. 8 , the virtual coordinate is set byconnecting the boundaries of the image each other. The boundaries of theimage are connected each other to form an annular shape. The motionvector may appears beyond the boundary or across the boundary. Like FIG.8 , only one boundary may be connected to each other to have a virtualcoordinate. However, depending on the type of the camera and theprojection type of the image acquired in (701), they may be connected inthe form of a polyhedron or a sphere and so may have complex connectionboundaries. In addition, because the boundary to be connected may varydepending on the number of cameras and the type of the projection, thevirtual coordinate setting may adaptively appear according to the image.If the virtual coordinate are obtained, the PMV candidate setting 704 ispossible according to the virtual coordinate. The motion vector in thevirtual coordinate 705 is calculated through the predictive motionvector and the transmitted differential motion vector. Then, a virtualmotion vector is calculated as a motion vector in a plane image(706),and then a reference region determination and compensation is performedusing the corresponding motion vector(707). If the virtual coordinateand the actual coordinate are the same, it may be performed without thevirtual coordinate setting step. For the convenience of the embodiment,the motion compensation is performed by calculating MV through thevirtual coordinate. However, It is possible to perform the motion vectorcalculation without the virtual coordinate according to the embodiment.That is, according to the embodiment, it is also possible to calculate,based on a method of converting coordinates using table mapping, themotion vector without the virtual coordinate and perform motioncompensation in a reference image. Although the embodiment does notinclude the step of designing the virtual coordinate, the table thatmaps the coordinates may include the virtual coordinate design. Inanother embodiment, the encoder may transmit the image informationincluding the coordinate setting or coordinate mapping table for thevirtual coordinate design. The decoder may perform conversion betweenthe actual coordinate and the virtual coordinate in the image using thecoordinate mapping table transmitted from the encoder. In anotherembodiment, virtual coordinates or coordinates may be fixed byappointments between the encoder and the decoder and the fixed virtualcoordinate value may be used. In the embodiment having a single virtualcoordinate value, the decoder performs motion vector calculation andmotion compensation using only predetermined virtual coordinate. When aplurality of fixed virtual coordinates are promised, the encoder maytransmit information indicating the corresponding virtual coordinate tothe decoder, or the decoder may obtain information relating to thevirtual coordinate by predicting based on the decoded image.

FIG. 9 is various embodiments in which an image of an omnidirectionalcamera is projected. FIG. 9A illustrates a projection onto a cube. Inthe embodiment, the number of sensors may be six so as to match thenumber of the respective projected planes, but fewer or more cases arepossible. When a projection is performed with a regular hexahedron,images of six planes are generated. To compress and transmit the images,one face may be composed of one frame as shown in FIG. 10A, or one framemay be constructed and transmitted using six images. At this time, theposition of the six faces in FIG. 10B may vary depending on theembodiment. In the embodiment of the present invention, since thecorresponding information may be used when the virtual coordinate isset, the encoder must transmit the corresponding information to thedecoder through the bitstream. The decoder may obtain the information at(701) and (702) and use it at the time of virtual coordinate design. Ofcourse, this information may be omitted if the information ispredetermined by a promise of the encoder and the decoder. The decodermay obtain the information through the promised matter even if it is notreceived from the encoder. FIG. 10C corresponds to an embodimentconstructing the projected image into one frame in case that the imageis projected onto a figure having 12 faces. The embodiment relate to amethod of projecting am image or images obtained by a camera having aplurality of sensors at the same time and constructing one frame forconvenience of compression and transmission. The method has variousforms according to the number of camera sensors and the projection type,and may vary depending on the embodiment.

FIG. 11 shows another embodiment relating to a projection type and amethod of constructing a frame. In FIG. 11 , the black shaded portion isthe portion where the acquired image is projected and the actual imagedata exists, and the white portion is the portion where the image datadoes not exist. Depending on the method of projection or the method ofconstructing the frame, the data may not exist in a form filled with ageneral rectangular frame. In this case, the encoder must transmit thecorresponding information to the decoder. According to an embodiment, awhite portion may be padded to form a rectangular frame, and then theframe may be encoded/decoded. Alternatively, only image data may beencoded/decoded without padding. In both methods, the encoder/decoderneeds to know and use the related information. The related informationmay be transmitted from the encoder to the decoder, or the relatedinformation may be determined by the promise of the encoder and thedecoder.

The present invention may be used in manufacturers such as broadcastingequipment manufacturing, terminal manufacturing, and industries relatedto original technology in video encoding/decoding related industries.

1-6. (canceled)
 7. A method of decoding image data, the methodcomprising: receiving a bitstream including a current picture of theimage data; acquiring, from the bitstream, image information of acurrent block in the current picture; decoding the current block basedon the image information; reconstructing the current picture based onthe decoded current block; and performing in-loop filtering on thereconstructed current picture, wherein decoding the current blockcomprises: constructing a motion vector candidate list, the motionvector candidate list including a plurality of motion vector candidates;determining a motion vector of the current block based on the motionvector candidate list and index information, the index informationspecifying one of the plurality of the motion vector candidates; andperforming a motion compensation on the current block based on thedetermined motion vector, wherein the motion vector candidate listincludes a motion vector of a pre-decoded block which is not adjacent tothe current block and belongs to the same coded picture as the currentblock.
 8. The method of claim 7, wherein the motion vector candidatelist further includes a motion vector of a spatial neighboring blockadjacent to the current block.
 9. The method of claim 8, wherein themotion vector candidate list further includes a third motion vector of atemporal neighboring block of the current block, and wherein thetemporal neighboring block is representative of a co-located block in areference picture.
 10. The method of claim 9, wherein determining themotion vector of the current block comprises: selecting, based on theindex information, one of the motion vector candidates in the motionvector candidate list; deriving a predictive motion vector of thecurrent block based on the selected motion vector candidate; anddetermining the motion vector of the current block by using thepredictive motion vector and a differential motion vector of the currentblock.
 11. A method of encoding image data, the method comprising:encoding a current block in a current picture of the image data;reconstructing the current picture based on the encoded current block;performing in-loop filtering on the reconstructed current picture; andgenerating a bitstream including image information of the current blockin the current picture, wherein encoding the current block comprises:constructing a motion vector candidate list, the motion vector candidatelist including a plurality of motion vector candidates; determining amotion vector of the current block based on the motion vector candidatelist; and performing a motion estimation on the current block based onthe determined motion vector, wherein index information specifying oneof the plurality of the motion vector candidates is encoded into thebitstream, and wherein the motion vector candidate list includes amotion vector of a pre-encoded block which is not adjacent to thecurrent block and belongs to the same coded picture as the currentblock.
 12. A device for storing a bitstream generated by an encodingmethod, wherein the encoding method comprises: encoding a current blockin a current picture of an image data; reconstructing the currentpicture based on the encoded current block; performing in-loop filteringon the reconstructed current picture; and generating the bitstreamincluding image information of the current block in the current picture,wherein encoding the current block comprises: constructing a motionvector candidate list, the motion vector candidate list including aplurality of motion vector candidates; determining a motion vector ofthe current block based on the motion vector candidate list; andperforming a motion estimation on the current block based on thedetermined motion vector, wherein index information specifying one ofthe plurality of the motion vector candidates is encoded into thebitstream, and wherein the motion vector candidate list includes amotion vector of a pre-encoded block which is not adjacent to thecurrent block and belongs to the same coded picture as the currentblock.